Making models in relief in gelatine by photographic processes



United States Patent() MAKING MODELS 1N RELIEF IN GELATINE BY PHOTOGRAPHIC PROCESSES Frank Debenham, Cambridge, England, assignor to Geographical Projects Ltd., London, England, a company of Great Britain Application .lune 14, 1949, Serial No. 99,124

Claims priority, application Great Britain November 15, 1948 5 Claims. (Cl. 95-5) This invention relates to a method of photographically producing maps which show relief eifects.

Individually, the principles applied in my method for making maps with relief effects have long been known, but so far as I am aware, I am the rst to apply these principles, in combination, to produce maps. My process is well adapted to the mass production of maps which instantly and clearly convey even to the uninitiated the three-dimensional characteristics of a given terrain.

Broadly, my process involves preparing an image of each contour level of the terrain under study, which images are arrangeable in sequence and in register, then photographically preparing from these images a gelatine mold of the given terrain at the desired enlargement or reduction. A cast of the terrain is then made from the gelatine mold. The cast is photographed in oblique light to give a shadow photograph of the vertical dimension of the terrain; and the shadow photograph, together with a photograph showing details of the horizontal area such as rivers, roads, etc., is combined into a photographic map at the desired scale, showing horizontal detail in the usual way and vertical detail by shadows. This combined map may be reproduced by any suitable printing process.

My process will now be described 1n connection with the accompanying drawing which is a ow diagram representing successive steps of one specific embodiment of the invention selected by way of example.

The most generally convenient way known to me for utilizing my process is as follows:

A transparent masking material such as tinted tracing paper, tinted cellophane or the like is placed over a contour map of the given terrain. Registration marks are made so that this sheet can be registered with other like sheets. The area surrounded by a given contour is cut out with a small cutting wheel. removed and the remaining area with its registration marks is photographed over a light background to the desired scale on stripping iilm, such as iilm having a gelatine-silver bromide emulsion on a collodion base which is backed by a regenerated cellulose or like exible supporting lm, slightly waxed to facilitate stripping of the emulsion and collodion base. Suitably polarized light is employed in obtaining the photograph on stripping film, and the camera is provided with an analyzer to eliminate glare. This process is carried out for a complete series of contours representing the vertical dimension of thev given terrain.

When the terrain is low-lying and the contours are few and far apart, it is simple and convenient to form images on the stripping lm of reduced horizontal scale and thus in effect to exaggerate the vertical scale which will inally be obtained. For example, negatives are produced for each of the cut out portions, these are placed in an enlarger and an image is projected onto the stripping lm. In this way it is possible to produce an image of any convenient size and the horizontal scale may be varied to the extent desired.

The next step is to develop the stripping lm and dip it in aqueous acetic acid, suitably of 20% strength, to act as a retarder during succeeding operations. The normal fixing procedure with thiosulphate is not employed. The stripping iilm is next immersed in an etch-bleach solution, for example a cupric chloride-hydrogen peroxide solution, until the silver image on the tilm has been bleached and the gelatine associated therewith has been softened. The softened gelatine is washed away,

The cut out portion is ICC suitably with the aid of a piece of cotton wool, leaving a clear image of the particular contour area in all its details, surrounded by unaffected gelatine in which the remaining silver will eventually be deposited by the action of light. l

Next, the gelatine and collodion base are stripped from the backing, starting with the sheet showing the highest contour level, and are laid down successively on a smooth base such as a glass plate, emulsion side down, and in register, and each is smoothed down against the one below, suitably with the aid of a chamois cloth, until it sticks to the sheet below. The very thin collodion backing to each sheet prevents displacement by the much thicker gelatine and also modies the stepped eiect.

The resulting structure is a gelatine model in intaglio of the given terrain. The trial collodion surface which is uppermost forms a smooth surface for casting. Moreover, this intaglio contains a deposit of silver in each layer of lilm, so that, if required, it can be used as a photographic density negative wherein the light transmission is proportional to contour level.

Casting is the next step of the process and may suitably be done in dental plaster or other tine-grained plaster which will not present surface imperfections even in an enlarged photograph. The cast is suitably dipped in hot wax and then polished, or varnished, or coated with a lm pendicularly to the plane of the cast and the light is di- Clt rected obliquely toward the cast at the angle selected to give the desired shadow length. This photograph may be made to any desired scale as by the use of a photographic enlarger-reducer and will preserve the ratio of vertical: horizontal scale of the cast. Thus whatever this ratio in the original contour map, it can be iixed at any desired value by the photographic processes employed in accordance with my invention.

The shadow photograph iinally is combined with a photograph showing details of the horizontal area, in a single print, as by any of the known means for forming superposed prints, which will then show both horizontal area details such as roads, rivers, etc., and the vertical dimension of the terrain by shadows.

Instead of obtaining the images to be photographed onto stripping iilm by cutting them out in tinted transparent material, l may obtain them in a variety of other ways. For example, the contour lines at each contour level may be traced onto clear, transparent sheets, registration marks may be made, and the areas outside the contours on each sheet may be opaqued. The resulting images of each contour may be photographed against a light background as before. Of if the map makers pull of the contour lines or contour areas are available, these may be photographed 'and the photographs may be opaqued as necessary to obtain the desired images to be photographed on stripping iilm. The above procedures are exemplary of preferred practice, but other methods of obtaining the desired negative images are not be considered as excluded.

An alternative to the etch-bleach process with stripping lm to obtain the desired gelatine vmodel photographically is use ofthe carbon process or the carbro (also called ozobrom) process for printing gelatine treated with dichromate solution (suitably potassium or sodium dichromate, or ammonium chromate or dichromate). Forexample, a gelatine model in intaglio may be obtained as follows. A series of negative photographic images of contour levels, or a series of cut out translucent or transparent tinted sheets such as used in the process described above, which series collectively represents the vertical dimension of the given terrain, is bound together in sequence and in register and is photographed against a light background. The result is a positive photographic image of the desired size inr which the density of the deposit in any part of the image represents the contour level of the given terrain at that location; or, in other words, the light transmission through the unage rat any point is inversely proportional to the 1 contour levelzof that. point.

This positive may then 'be printed using the carbon process, e. g. printed -on a gelatine-sugar-or-gelatine-glyc erine coated film which hasfbeen soaked in cold aqueous potassium dichromate solution of '3l-5%. strength. Sultablyv :a double.iorvftriplezdayer of gelatine (t1. f e. about 0.03-:,0.05 :inch '.thick )=on-a .clear .support,-.such asncellulose. acetate :or 4thin glass ijs .employed .and preferably the printing istdone: while vthengelatine is.still tdamp, -to avoid curling. The positive is smoothed down inshghtly damp `nonditionagainstthe-baek of ttheclearA support :and lightis passed :through :the positive. The '.tneated ,gelatine becomesfwaterfinsolublein .proportion tto its .exposure tto light; :that `which is belowv the darketareasA of the positive is unaffected. Ihe treatment isucontfinued :until insolubilization '.belowrzclear regions .of fthe ipositive has .been effected through tth'e :full depth :of `the treated Lgelatine layer. 'When :the exposed- .gelat-ine dsfiwashed :in ywarm water, lthe igelatine :which :remains soluble is removed, leaving a ;low ,gelatineintaglio'toftthe .givenzterrain on Athe backing.

ItLis necessary to accentuate mheintaglio forsatisfactory casting. .'Ehisimaytbeaaccomplished =by.:soaking say 2'4 hours'in cold water,or;in shortertime using warm water, or weakly :acid 4.or-.'weakly alkalinesolution,l for lexam-V ple an aqueous ammonia tsolutiontof-:pH about :8; 'This operation increases ithetdepthfof ftheoriginal intagliofby some S-foldfas` a yresult `of swelling of the gelatine. The gelatine ymold may;now be :toughened .by treatmentfwith chrome .alum `solution, say 5. minutes, :soaking iin V4% solution..A

Gelatine swollen as above even if toughened is very tender `and accordinglymmust 4be protected ffrom'` the aqueous menstrum used `with plaster :for casting. SI have found that a film of .collodion over .theagelatine :mold serves ythe purpose. Such aifilmvmaybe obtainedtlby placing-the mold under water-with :arrangements (wires or #the like) .forraising thewmo'ld outof lwater `when .desired.. A drop :or .two'ofzthin.collodionsolution -is kadded and ,when .the solution hasA spread over the surface of .the water and just .as it isgheginning to set, the-.gelatine mold isfslowly `raised .out .offwatenv A:water-.imperyious tilm of tgllodion iis deposited raver :the surface lofzthe gelatine mo Agplaster cast may .bernaderfrom `this gelatine .mold and therremaining* 'operationszmay :be carried tout as has already beendescribed.

As another :specific example. -of tphotographically olb taining Va gelatine ,mold ,ofi the given merrain, a method combining the Ause `of the etch-bleach process with a Vbichromatedgelatine processvmay befcited. In this-meth od .the ycut lout or. negative photographic images iofthe given terrain .are bound "together gin vsequence `and registerand aphotograph of-the desiredssize'is taken in-double thickness silver :bromide .emulsion 'in gelatine on a glass backing. The photograph. a rpositive :is developed but not fixed.

Etchfbleach solution is then applied to :this1positive in .the light andthe .action is continued .untilra negative relief (an intaglio) -OFfthegivenfterrain has been .obtained. In this intaglioa further-:amount of silvertdeposit forms in the remaining gelatine -,as a fresult of the action of vlightton theemulsion, `the .amount .of ysilver deposited `being proportional -.to the .thickness of gelatine re-` maining atany point. Thus .there vis obtained .adensity negative of the terrain, combined with lanegativerelief of the terrain.

After the vdensity negative ,has been `developed and fixed, a carbro process print ,is made from the Idensity negative by squeegeeing, to the face of :the negative, carbon vtissue ydouble coated `with .gelatinesensitized :for carbro printing. lInteraction:betweenthe deposit on .fthe negative and the`sensitized,gelatine,insolubilizes gelatine in proportion to the densityof thessilver deposit, `tine. in proportion to the degree ,of trelief :pre-existing :in .the density negative. The Icarbon tissue fbacking `:is lthen stripped off in warm water, andfzsolublegelatineis-washed away, Vleaving tan laccentuated negative relief composed of gelatine of the silver bromide .emulsioneplus .gelatine from the` carbon tissue. ,Thisrelie'fmaybe further accentuated rby'swellingin .aqueous medium as previously described, and coated with collodion. :It is used as amold for a plaster castand` the vprocess-,proceeds asbefore.

The --abovef described specific' embodimentsrofmy invention illustratetpreferredimodes yoftohtaining photographically the desired gelatine moldfbut azeinotzthe/onlyfways Cfr in which it may be obtained inasmuch as modifications ofthe'above wrill -be evident to one skilledin the photographic art.

If desired, my final map may be prepared to show contour level by color as well asby shadow. For example, a density positive may be made, e. g. from a denslty negativeobtained bycthe process. of my invention as described above, and .may .be-printed on the finished map in the color desired for high areas; and a density negative may similarly 4.be .printed in the Ycolor signifying low areas. The ftwo combined ,on fthe final map vwill Vthen .shade into each other as the terrain alters from low :to high. The printing in this modification of my process may be carried out by any convenient -color printing means, as well known in the .photographic art.

Where, in the above description vof specific embodiments of my process, it is stated that negative images and gelatine intaglios are made, it yis possible to make positives and gelatine reliefs by similar procedures, mutatis mutandis; but in general lit is vpreferred toobtain a gelatine intaglio to 'zbe used asathemold for casting,^rather than to .obtain -a gelatine relief.v

What I -claim .and desire to secure yby Letters Patent is:

l. A process lfor the production of maps showing details of both the horizontal and the vertical dimensions of a `'given terrain, which process comprises forming .a separate image record :on 4sheet material of the outline .of each successive Acontour level fof. .the terrain, said image records being vdimensionedto .be superposed in sequence and in register with oneganother, each of said image recordshaving a light-,contrast between ,areas above and areasi below Athe contour level represented by the respective ,image record, photographically reproducing said image records` ongelatinesheet material sensitized so that the solubility `of the sheet varies with exposure to light, whereby the light-contrast of said image records is reproduced ,in .solubility-contrast vof said ,gelatine material, washing away the vmore Isoluble gelatine lmaterial while leaving the jless .soluble ,gelatine material to provide differencesA in :thickness corresponding to said light-contrast, .sheets-representing lthe. respective contours being superposedon one-another inregistration and in order to form a contoured `surfacze :that fis an ,intaglio representation-.of the terrain, ormingafcast of said `contoured surface, photographing ,the .cast with yoblique lighting to produce a shadowphotographpf -the Avertical dimension of'the terrain, .-and Combining this :shadow photograph with a photograph showing Vdetails of the terrain in `the horizontal dimensions to produce 4a printshowing details of the terrainin ,the horizontal dimensions and details of the vertical dimension 'by shadows.

.2. Jnya process of producing :maps *showing details of both `the horizontal rand-the vertical dimensions of a terrain, lthe-.stepsof providing a map lshowing successive contour levels, making a separate image record on sheet materialv ofthe outline of each of selected contour levels of the terrain, each ofsaid image records having a light-contrast betweenaareas Aabove and areas below the contour level represented by the frespective `image record, photographically yreproducingeach `of said image Arecords on a sheet of gelatinous material sensitized so that the solubilityof the gelatinous material varies with exposure to light, removing ,the more soluble gelatinous material so that the area ofthe gelatinous s'heet on one side of the contour .outline -is thicker than on rthe opposite side, and superposing said gelatinous sheets in registration with one another to forma relief lrepresentation of said terrain.

3. In a .process of producing maps showing details of both the Vhorizontal and ithe vertical-dimensions of a terrain, the steps'of providing a map showing successive contour 1evels,;making aiseparate image record'on sheet materialtof-'the outline o'feach--of selectedecontour levels of the terrain, eachof` said "image lrecords having a jlightcontrastbetweenareas'above and areas below the contour level represented 'by the respective image record, photographically reproducing each Io'f said image records on a composite.sheetcomprising a thin -exible backing and a layer :ofngelatinous material'sensitized so that `the solubilityof the gelatinous material lvaries with exposure 'to light, :removing Athe more `soluble portionsp'f. the gelatinousmaterial softhattthe area-of the composite sheet'on one side fofthe contour-outline vis Athicker than on ,the opposite side, and lsuperposing said ycomposite'sheets Ain registration :with y one t another to form a relief 'representa-` tion,A of saidlterrain.

4. In a process of producing maps showing details of both the horizontal and the vertical dimensions of a terrain, the steps of providing a map showing successive contour levels, making a separate image record on sheet material of the outline of each of selected contour levels of the terrain, each of said image records having a light-contrast between areas above and areas below the contour level represented by the respective image record, photographically reproducing each of said image records on a composite sheet comprising a supporting sheet, a thin exible backing and a layer of gelatinous material sensitized so that the solubility of the gelatinous material varies with exposure to light, the exposure of said composite sheet being such that the gelatinous material in the area representing the map area above the respective contour level is rendered more soluble than that in the area representing the rnap area below said contour level, removing the more soluble portions of the gelatinous material and stripping the backing and attached layer of gelatinous material from the supporting sheet and superposing said backings with the attached gelatinous material in registration and in order, starting with the highest contour, the backings being placed with the gelatinous sides down, the superposed layers of gelatinous material forming an intaglio representation of the terrain and the backings tending to smooth out the steps presented by successive layers.

5. In a process of producing maps showing details of both the horizontal and the vertical dimensions of a terrain, the steps of providing a map showing successive contour levels, making an image record on sheet material of the outline of each of selected contour levels of the terrain, each of said image records having a light-contrast 0 Number between areas above and areas below the contour level represented by the respective image record, photographically reproducing each of said image records on a composite sheet comprising a thin flexible backing and a layer of gelatinous material sensitized so that the solubility of the gelatinous material varies with exposure to light, the exposure of said composite sheet in making said photographic reproduction being such that the gelatinous material in the area representing the terrain area above the respective contour level is rendered more soluble than that in the area representing the terrain, removing the more soluble portions of the gelatinous material, superposing said composite sheets in registration with one another starting with the highest contour, the backing of said sheets being placed uppermost, the superposed layers of gelatinous material forming an intaglio representation of the terrain and the backing tending to smooth out the steps presented by successive layers.

References Cited in the tile of this patent UNITED STATES PATENTS Name Date Jacobson .Tune 15, 1897 Heise May 5, 1936 Tour Feb. 2, 1937 Wenschow Mar. 28, 1939 FOREIGN PATENTS Country Date Great Britain Oct. 9, 1924 Great Britain Oct. 5, 1931 Number 

2. IN A PROCESS OF PRODUCING MAPS SHOWING DETAILS OF BOTH THE HORIZONAL AND THE VERTICAL DIMENSIONS OF A TERRAIN, THE STEP SO PROVIDING A MAP SHOWING SUCCESSIVE CONTOUR LEVELS, MAKING A SEPARATE IMAGE RECORD ON SHEET MATERIAL OF THE OUTLINE OF EACH OF SELECTED CONTOUR LEVELS OF THE TERRAIN, EACH OF SAID IMAGE RECORDS HAVING A LIGHT-CONTRAST BETWEEN AREAS ABOVE AND AREAS BELOW THE CONTOUR LEVEL REPRESENTED BY THE RESPECTIVE IMAGE RECORD, PHOTOGRAPHICALLY REPRODUCING EACH OF SAID IMAGE RECORDS ON A SHEET OF GELATINOUS MATERIAL SENSITIZED SO THAT THE SOLUBILITY OF THE GELATINOUS MATERIAL VARIES WITH EXPOSURE TO LIGHT, REMOVING THE MORE SOLUBLE GELATINOUS MATERIAL SO THAT THE AREA OF THE GELATINOUS SHEET ON ONE SIDE OF THE CONTOUR OUTLINE IS THICKER THAN ON THE OPPOSITE SIDE, AND SUPERPOSING SAID GELATINOUS SHEETS IN REGISTRATION WITH ONE ANOTHER TO FORM A RELIEF REPRESENTATION OF SAID TERRAIN. 